Obviously, there is a lot to do and see in Lisbon proper. We have a walking tour we take visitors on which can be broken up into a couple of days or done in one, relatively aggressive day (with many cuts from the list below).
If you break it up, we suggest:
Day One – start out at the Praça do Comercial where Lisbon meets the Tagus River. There’s a lot to explore there including the cafes and the Lisboa Story Center which is a good museum for kids telling the story of Lisbon. From there, you can climb the hill into the Alfama neighborhood where you can visit the Se (the Cathedral), the Castelo de São Jorge (the Castle atop the hill), and the Roman Ruins nearby. Stop for lunch (on the back side of the Castle is Cervejeria Ramiro but you may want to take a Tuk Tuk or cab there or hit it for lunch on day two as there are lots of good lunch options in Alfama proper) and check out several of the Miradouros (viewpoints) of the city, castle and the river. Another great view of the city can be obtained from the roof of the Pantheon. If you’re staying overnight, check out the Fado music in one of the many Fado bars near the Se. There are lots of dining options as well. Our first four nights in Portugal were spent in Alfama and it has a special place in our hearts. The Military Museum (museu militar) and Fado Museum are also worth checking out, if you have the time.
Day Two – Explore the Santa Justa lift, the Convento do Carmo and Rossio Square. Eat lunch in Bairro Alto (or hit up Ramiro up the road from Rossio referenced above and have dinner in Bairro Alto instead). There are any number of good spots by the Convento do Carmo. This is also a great neighborhood in which to stay over if you’re overnighting.
Day Three – a short train ride from Cais do Sodre train station in Lisbon, you can catch the train to Belém. Belém is home to the Belém Tower, the Jerónimos Monastery and the monument to the discoveries (Padrão dos Descrobrimentos). Lots of good spots for seafood along the river. If you didn’t already try Pastel de Nata in Alfama you can get the original here in Belém, be ready to wait in line. Also, you can watch them change the guard on the third Sunday morning of each month at the Belém Palace.